It happened at 3:30 p.m. Wednesday at the Town and Country Shopping Center at Harvey Road and Philadelphia Pike.
Delaware State Police say the driver, an 83-year-old woman from Claymont, lost control and drove through the front wall of Richard's Deli.
The driver's 35-year-old grandson was also in the car.
Images from the scene showed the 2006 Saturn Ion completely inside the business.
The accident caused extensive damage to the refrigerated display cases and an office.
Two people were treated at the scene for minor injuries.
There was no immediate word what caused the drive to lose control.